The resent invention is directed to recording sheets, such as transparency materials, filled plastics, papers, and the like. More specifically, the present invention is directed to recording sheets particularly suitable for use in ink jet printing processes. One embodiment of the present invention is directed to a recording sheet which comprises (a) a base sheet; (b) a material selected from the group consisting of tetrazolium compounds, indolinium compounds, imidazolinium compounds, and mixtures thereof; (c) an optional pigment; and (d) an optional binder.
Recording sheets suitable for use in ink jet printing are known. For example, U.S. Pat. No. 4,740,420 (Akutsu et al.) discloses a recording medium for ink jet printing comprising a support material containing at least in the surface portion thereof a water soluble metal salt with the ion valence of the metal thereof being 2 to 4 and a cationic organic material. The cationic organic materials include salts of alkylamines, quaternary ammonium salts, polyamines, and basic latexes.
U.S. Pat. No. 4,576,867 (Miyamoto) discloses an ink jet recording paper with improved water resistance and sunlight fastness of the image formed on the paper wherein the recording paper has attached to its surface a cationic resin of the formula ##STR1## wherein R.sub.1, R.sub.2, and R.sub.3 represent alkyl groups, m represents a number of 1 to 7, and n represents a number of 2 to 20, and Y represents an acid residue.
U.S. Pat. No. 4,446,174 (Maekawa et al.) discloses an ink jet recording method for producing a recorded image on an image receiving sheet with a jet of aqueous ink, wherein an ink jet is projected onto an image receiving sheet comprising a surface layer containing a pigment, and wherein the surface layer is capable of absorbing a coloring component in the aqueous ink. Poly(vinyl benzyl trimethyl ammonium chloride), poly(diallyl dimethyl ammonium chloride), and poly(methacryloxyethyl-.beta.-hydroxyethyl dimethyl ammonium chloride) are disclosed as dye absorbing adhesive materials.
U.S. Pat. No. 4,830,911 (Kojima et al.) discloses a recording sheet for ink jet printers which gives an image by the use of an aqueous ink containing a water-soluble dye, coated or impregnated with either of or a mixture of two kinds of water soluble polymers, one whose polymeric unit is alkylquaternaryammonium(meth)acrylate and the other whose polymer unit is alkylquaternaryammonium(meth)acrylamide, wherein the water soluble polymers contain not less than 50 mol percent of a monomer represented by the formula ##STR2## where R represents hydrogen or methyl group, n is an interger from 1 to 3 inclusive, R.sub.1, R.sub.2, and R.sub.3 represent hydrogen or the same or different aliphatic alkyl group with 1 to 4 carbon atoms, X represents an anion such as a halogen ion, sulfate ion, alkyl sulfate ion, alkyl sulfonate ion, aryl sulfonate ion, and acetate ion, and Y represents oxygen or imino group.
U.S. Pat. No. 4,554,181 (Cousin et al.) discloses an ink jet recording sheet having a recording surface which includes a combination of a water soluble polyvalent metal salt and a cationic polymer, the polymer having cationic groups which are available in the recording surface for insolubilizing an anionic dye.
U.S. Pat. No. 4,877,680 (Sakaki et al.) discloses a recording medium comprising a substrate and a nonporous ink receiving layer. The ink receiving layer contains a water-insoluble polymer containing a cationic resin. The recording medium may be employed for recording by attaching droplets of a recording liquid thereon.
European Patent Publication 0 439 363 A1, published Jul. 31, 1991, corresponding to U.S. Pat. No. 5,302,249, filed Jan. 25, 1990, the disclosure of which is totally incorporated herein by reference, discloses a paper which comprises a supporting substrate with a coating comprising (a) a desizing component selected from the group consisting of (1) hydrophilic poly(dialkylsiloxanes); (2) poly(alkylene glycol); (3) poly(propylene oxide)-poly(ethylene oxide) copolymers; (4) fatty ester modified compounds of phosphate, sorbitan, glycerol, poly(ethylene glycol), sulfosuccinic acid, sulfonic acid and alkyl amine; (5) poly(oxyalkylene) modified compounds of sorbitan esters, fatty amines, alkanol amides, castor oil, fatty acids and fatty alcohols; (6) quaternary alkosulfate compounds; (7) fatty imidazolines; and mixtures thereof, and (b) a hydrophilic binder polymer. The binder polymer may be a quaternary ammonium copolymer such as Mirapol WT, Mirapol AD-1, Mirapol AZ-1, Mirapol A-15, Mirapol-9, Merquat-100, or Merquat-550, available from Miranol Incorporated.
U.S. Pat. No. 5,223,338, filed Apr. 1, 1992, the disclosure of which is totally incorporated herein by reference, discloses a recording sheet which comprises a substrate and a coating consisting essentially of (1) quaternary ammonium polymers selected from the group consisting of (a) polymers of Formula I ##STR3## wherein n is an integer of from 1 to about 200, R.sub.1, R.sub.2, R.sub.3, and R.sub.4 are each independently selected from the group consisting of alkyl groups, hydroxyalkyl groups, and polyoxyalkylene groups, p is an integer of from 1 to about 10, q is an integer of from 1 to about 10, X is an anion, and Y.sub.1 is selected from the group consisting of --CH.sub.2 CH.sub.2 OCH.sub.2 CH.sub.2 --, --CH.sub.2 CH.sub.2 OCH.sub.2 CH.sub.2 OCH.sub.2 CH.sub.2 --, --(CH.sub.2).sub.k --, wherein k is an integer of from about 2 to about 10, and --CH.sub.2 CH(OH)CH.sub.2 --; (b) polymers of Formula II ##STR4## wherein n is an integer of from 1 to about 200, R.sub.5, R.sub.6, R.sub.7, and R.sub.8 are each independently selected from the group consisting of alkyl groups, hydroxyalkyl groups, and polyoxyalkylene groups, m is an integer of from 0 to about 40, r is an integer of from 1 to about 10, s is an integer of from 1 to about 10, X is an anion, and Y.sub.2 is selected from the group consisting of --CH.sub.2 CH.sub.2 OCH.sub.2 CH.sub.2 --, --CH.sub.2 CH.sub.2 OCH.sub.2 CH.sub.2 OCH.sub.2 CH.sub.2 --, --(CH.sub.2).sub.k --, wherein k is an integer of from about 2 to about 10, and --CH.sub.2 CH(OH)CH.sub.2 --; (c) copolymers of Formula iii ##STR5## wherein a and b are each integers wherein the sum of a+b is from about 2 to about 200, R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, R.sub.7, and R.sub.8 are each independently selected from the group consisting of alkyl groups, hydroxyalkyl groups, and polyoxyalkylene groups, p is an integer of from 1 to about 10, q is an integer of from 1 to about 10, X is an anion, and Y.sub.1 and Y.sub.2 are each independently selected from the group consisting of --CH.sub.2 CH.sub.2 OCH.sub.2 CH.sub.2 --, --CH.sub.2 CH.sub.2 OCH.sub.2 CH.sub.2 OCH.sub.2 CH.sub.2 --, --(CH.sub.2).sub.k --, wherein k is an integer of from about 2 to about 10, and --CH.sub.2 CH(OH)CH.sub.2 --; (d) mixtures of polymers of Formula I and polymers of Formula II; (e) mixtures of polymers of Formula I and copolymers of Formula III; (f) mixtures of polymers of Formula II and copolymers of Formula III; and (g) mixture of polymers of Formula I, polymers of Formula II, and copolymers of Formula III; (2) an optional binder polymer; and (3) an optional filler.
U.S. Pat. No. 5,212,008, filed Apr. 1, 1992, the disclosure of which is totally incorporated herein by reference, discloses a recording sheet which comprises a substrate; a first coating in contact with the substrate which comprises a crosslinking agent selected from the group consisting of hexamethoxymethyl melamine, methylated melamine-formaldehyde, methylated urea-formaldehyde, cationic urea-formaldehyde, cationic polyamine-epichlorohydrin, glyoxal-urea resin, poly(aziridine), poly(acrylamide), poly(N,N-dimethyl acrylamide), acrylamide-acrylic acid copolymer, poly(2-acrylamido-2-methyl propane sulfonic acid), poly(N,N-dimethyl-3,5-dimethylene piperidinium chloride), poly(methylene-guanidine)hydrochloride, poly(ethylene imine)poly(ethyleneimine)epichlorohydrin, poly(ethylene imine)ethoxylated, glutaraldehyde and mixtures thereof; a catalyst; and a polymeric material capable of being crosslinked by the crosslinking agent and selected from the group consisting of polysaccharides having at least one hydroxy group, polysaccharides having at least one carboxy group, polysaccharides having at least one sulfate group, polysaccharides having at least one amine or amino group, polysaccharide gums, poly(alkylene oxides), vinyl polymers, and mixtures thereof; and a second coating in contact with the first coating which comprises a binder and a material selected from the group consisting of fatty imidazolines, ethosulfate quaternary compounds, dialkyl dimethyl methosulfate quaternary compounds, alkoxylated di-fatty quaternary compounds, amine oxides, amine ethoxylates, Imidazoline quaternary compounds, alkyl benzyl dimethyl quaternary compounds, poly(epiamines), and mixtures thereof.
While known compositions and processes are suitable for their intended purposes, a ned remains for improved recording sheets. In addition, there is a need for improved recording sheets suitable for use in ink jet printing processes. Further, a need remains for recording sheets for ink jet printing with a high degree of waterfastness. Additionally, there is a need for paper recording sheets for ink jet printing with reduced showthrough of the images on the side of the paper opposite to that printed. There is also a need for recording sheets for ink jet printing with enhanced optical density.